Hermetically sealed dynamoelectric machine

ABSTRACT

Effective spray cooling of the stator of a hermetically sealed motor is achieved without a reduction in stator flux carrying capacity by passing fluid refrigerant through triangularly shaped axial channels situated entirely within the stator teeth. Desirably, the edges of the channels are disposed parallel to the tapered faces of their associated teeth and the flux carrying area of each tooth is equal to the flux carrying area of the tooth face confronting the motor air gap. In one embodiment of the invention, entry of fluid refrigerant to the axial channels within the teeth is accomplished utilizing a diversely apertured annular manifold centrally positioned along the stator core and the refrigerant is withdrawn at both ends of the motor. Other refrigerant flow configurations, e.g., admitting the refrigerant at both ends of the motor and exhausting the refrigerant at the center or both ends of the motor, also are described.

Lenz

[54] HERMETICALLY SEALED DYNAMOELECTRIC MACHINE [72] Inventor: HenryGeorge Lenz, Scotia, NY.

{73] Assignee: General Electric Company [22] Filed: Jan. 4, 1971 211App]. No.: 103,497

[52] US. Cl.... ..310/54, 310/59 [51] Int. Cl. ..H02k 9/10 [58] Field ofSearch ..310/54-65 [56] References Cited UNITED STATES PATENTS R26,7761/1970 Anderson et al ..310/64 X 1,448,700 3/1923 Seidner... ....310/64X 3,217,193 11/1965 Rayner ..310/54 3,241,331 3/1966 Endress et a1..310/54 X FOREIGN PATENTS OR APPLlCATlONS 1,090,750 10/1960 Germany..310/64 EVA PORATOR COMPRESSOR Primary ExaminerD. F. Duggan Att0meyJohnJ. Kissane, James C. Davis, Jr., Frank L. Neuhauser, Oscar B. Waddelland Joseph B. F orman [57] ABSTRACT Effective spray cooling of thestator of a hermetically sealed motor is achieved without a reduction instator flux carrying capacity by passing fluid refrigerant thrOughtriangularly shaped axial channels situated entirely within the statorteeth. Desirably, the edges of the channels are disposed parallel to thetapered faces of their associated teeth and the flux carrying area ofeach tooth is equal to the flux carrying area of the tooth faceconfronting the motor air gap. In one embodiment of the invention, entryof fluid refrigerant to the axial channels within the teeth isaccomplished utilizing a diversely apertured annular manifold centrallypositioned along the stator core and the refrigerant is withdrawn atboth ends of the motor. Other refrigerant flow configurations, e.g.,admitting the refrigerant at both ends of the motor and exhausting therefrigerant at the center or both ends of the motor, also are described.

9 Claims, 8 Drawing Figures COND ENSOR July 4, 1972- P'ATENTE DJuL 419723,675,056

. SHEET 10F 5 EVA PORATOR COMPRESSOR CONDENSOR FIGJ INVENTOR. HENRY G.LENZ HIS ATTORNEY PATENTEDJUL 4 m2 SHEET 2 OF 5 F'IG.2

PATENTEDJUL 4 1972 TEMPERATURE F) CONDENSING VALVING j A EVAPORATI ONCOMPRESSION 8.3 y .l E NTHALP) (BTU/L8) 87 FIG-.4

REFRlG-ERANT' F'RQN j CONDENSER T FIGS L7 TO EVAPORATOR PATENTEDJUL41972 3,675,056

sum u or 5 FIG. 6

EVAPORATOR REFRIGERANT FROM CONDENSER FIG. '7

TO EVA POR ATO R FROM PATENTEDJUL 4 1972 3, 75,056

sum 5 or 5 To EVAPORATOR \A REFRIGERANT FROM l CONDENSER FIG. 8

HERMETICALLY SEALED DYNAMOELECTRIC MACHINE This invention relates tohermetically sealed dynamoelectric machines and in particular, tomachines having triangularly shaped apertures disposed in apre-determined position entirely within the stator teeth to optimizecooling of the machine without adversely affecting the flux carryingcapacity of the stator.

The primary limitation restricting the generated output of hermeticallysealed machines is heat generated by current flow in the stator windingsand a number of techniques heretofore have been proposed to alleviatethis problem. For example, insulating spacers have been inserted betweenstator windings to provide flow channels for axial passage ofrefrigerant in a liquid or gaseous state through the stator slots forremoval of generated heat. Refrigerant flow channels within the slots,however, necessarily reduce the area available for the machine windingsand the output of the machine therefore is limited.

Removal of heat generated by the stator windings also has beenaccomplished utilizing ductsextending longitudinally and/or radiallythrough the stator laminations for refrigerant flow channels. Typically,these ducts have taken the configuration of circular apertures withinthe stator yoke, rectangular apertures within the stator teeth, radialducts at intervals along the stator core and triangularly shapedapertures extending between the stator teeth and the yoke. When aportion of the yoke is removed to provide the refrigerant flow channels,however, the flux density increases adversely affecting the power factorand material utilization of the machine.

It is therefore a primary object of this invention to provide adynamoelectric machine wherein optimum cooling of the stator is achievedwithout compromising the flux carrying capacity of the stator yoke.

Many of the fluid cooling systems of the prior art alsocharacteristically admit the refrigerant directly into the end turncavity of the motor so that the refrigerant impinges directly upon thestator endtums at high velocity. While impingement of the refrigerantdirectly upon the exposed end turns often is not undesirable, in somesituations, e.g. where solid particles are contained within therefrigerant, the high velocity possessed by the refrigerant droplets canhave a deleterious effect upon the end turn insulation.

lt is therefore a secondary object of this invention to provide adynamoelectric machine wherein spray cooling is achieved withoutimpinging liquid refrigerant at high velocities upon the machine endturns.

It is also an object of this invention to provide a dynamoelectricmachine characterized by a minimum temperature variation along thelength of the machine.

These and other objects of the invention generally are achieved by theutilization of triangularly shaped apertures situated entirely withinthe stator teeth as axial flow channels for the fluid refrigerant. Thus,a dynamoelectric machine in accordance with this invention generallywould include a cylindrical stator formed of a plurality of stackedmagnetic laminations characterized by a homogeneous circular yoke and aplurality of selectively apertured teeth extending radially inwardlyfrom the yoke. Each of the teeth sides are tapered at an angle toproduce parallelly disposed slot walls for insertion of machine windingstherein and a triangularly shaped aperture is located entirely withineach stator tooth at an attitude producing constant flux carrying areaover the length of the tooth, i.e. the total magnetic area of the toothstruts adjacent each triangularly shaped aperture is made substantiallyequal to the flux carrying area of the tooth face confronting thecylindrical rotor bore formed interiorly of the stator laminations.Means also are provided in the machine for passing a fluid refrigerantthrough the triangularly shaped apertures in an axial direction.

While the present invention is particularly defined in the appendedclaims, a more complete understanding of the basic principles of thisinvention can be achieved from the following detailed description ofvarious specific embodiments taken in conjunction with the attacheddrawings wherein:

FIG. 1 is a sectional view illustrating a hermetically sealed, spraycooled motor in accordance with this invention,

FIG. 2 is a partially broken away plan view of a stator laminationdepicting the disposition of the refrigerant flow channels within thestator teeth;

FIG. 3 is a partially broken-away -away plan view of the manifoldemployed to difi'use fluid refrigerant within the motor,

FIG. 4 is a graph portraying a typical temperature-enthalpy cycle of therefrigerant during motor operation, and,

FIGS. 5-8 are sectional views illustrating alternate refrigerant flowpaths employable with motors formed in accordance with this invention.

A hermetically sealed induction motor 10 fabricated in accordance withthis invention is illustrated in FIG. 1 and generally comprises a rotor12, a stator 14 circumferentially disposed about the rotor forelectromagnetic interaction therewith and a cylindrical housing 16hermetically sealing the motor interior in association with end plates18. Typically, rotor 12 can be of conventional squirrel cage design anddesirably possesses a plurality of axially extending fan blades 20situated at arcuately displaced locations along both ends of the rotorto distribute refrigerant uniformly throughout the end turn cavity.Suitably, the fan blades may be aluminum cast simultaneously with thecasting of the rotor conductors (not shown) while the illustrated statoris fabricated of form wound coils 22 connected in conventional fashionfor motor operation. Other refrigerant distribution techniques, e.g.,nozzles disposed around the shaft, passages in the rotor end rings,etc., also could be used in place of the fan blades, if desired.

A shaft 24 passes axially through rotor 12 and has opposite endssupported by bearings 26 within end plates 18 to permit rotation of therotor relative to the fixedly positioned stator. It will be appreciatedthat motor 10 also would include other conventional features such as,for example, bearing seals, which are not illustrated for purposes ofclarity.

Stator 14 is composed of a plurality of stacked magnetic laminations 28,illustrated in FIG. 2, having a homogeneous circular yoke 30 and aplurality of selectively apertured teeth 32 extending radially inwardlytherefrom. Each of the teeth have linearly tapered sides 34 to provideparallel side walls for axially extending slots formed between the teethof the stacked laminations to snugly accept rectangular form wound coilsides 35 therein. In accordance with this invention, each tooth ischaracterized by a triangularly shaped aperture 36 situated entirelywithin the tooth at an attitude to provide a flux carrying area alongthe tooth length equal to the flux carrying area of tooth face 38confronting the rotor bore, i.e. the total area of the tooth struts 41formed adjacent each aperture is equal at any radial location to thetotal area of tooth face 38. To achieve this result, the sides of eachaperture are disposed parallel to the adjacent tapered side of the toothat an attitude to converge at the center of tooth face 38. However, fortooling convenience and to increase the rigidity of the teeth, theinternal angles of the stamped triangular apertures preferably arerounded (producing a slightly trapezoidal configuration in the stampedapertures) and apertures 36 of the preferred illustrated embodimenttherefore do not extend entirely to the tooth face. In'light of theforegoing, it will be appreciated tat the term triangular apertures asused in this specification, also includes geometric shapes ditferingslightly from a pure triangular configuration. For example, the termwould include trapezoidal apertures wherein the non-parallel sides ofthe trapezoid are parallel to the adjacent sides of the teeth and thelengths of the parallel sides difier by a substantial amount, i.e.,normally by at least a factor of four.

Notwithstanding the reduction of tooth rigidity produced by extension ofthe converging sides of apertures 36 to tooth face 38, suchconfiguration can be desirable to provide fluid communication betweenthe triangular apertures and the air gap 40 of the motor. In such event,a plurality of magnetic laminations (not shown) having teeth totallydissected by the triangular apertures preferably are secured, e.g. usingepoxy resin adhesives, to laminations having triangular apertures withrounded edges (as illustrated in FIG. 2) to reduce the attendant loss ofrigidity. When the stator subsequently is formed in conventionalfashion, the stator will exhibit fluid refrigerant communication betweenthe triangular apertures and the air gap through the totally dissectedteeth while possessing mechanical rigidity imparted to the stator teethby those laminations having rounded edges adjacent tooth face 38.

In accordance with this invention, triangular apertures 36 within eachtooth are located entirely within the confines of the tooth, i.e. thetriangular apertures do not extend into yoke 30, and the top of thetriangular apertures preferably lie along the radial inner circumferenceof the yoke to provide maximum cooling surface for the stator. Ifdesired, however, the apertures could terminate slightly interior of thetooth/yoke interface without significantly effecting the coolingcharacteristics of the stator. Because the most restricted section ofthe tooth, e.g. tooth face 38 confronting the air gap, is employed todetermine the strut area to remain after aperturing of the stator teeth,the flux carrying capacity of each tooth is maintained at a maximumvalue along the entire length of the tooth. Moreover, because the yokeis not apertured, optimum utilization of the flux carrying capacity ofthe yoke is obtained and localized heating of the yoke is inhibited.

To communicate the liquid refrigerant with the triangularly shapedapertures within the stator teeth, an annular manifold 42, illustratedin FIG. 3, having a diameter preferably less than the diameter ofmagnetic laminations 28 is situated centrally along the stator core toform an annular liquid refrigerant reservoir 44 between the exteriorsurface of the manifold and radially removed motor housing 16. Aplurality of rectangular plates 46 extend radially inwardly from themanifold to overlie one strut of each apertured tooth and the platespreferably are mechanically secured, e.g. by welding, to the adjacentmagnetic lamination to fixedly position the manifold prior to stackingthe laminations to form the stator. Four of the plates, i.e. plates 46A,situated at a 45 angle relative to the vertical and horizontal centerlines of the stator are completely solid and serve to divide themanifold into four relatively isolated sections while the remainingplates forming the manifold, i.e. plates 46B, have rectangular apertures48 (illustrated in FIG. 1) situated along the upper portion of theplates to permit fluid communication between areas located on oppositesides of the plates. Suitably the plates may be made of any mechanicallystrong material, for example, steel, and preferably should have athickness slightly less than the width of a strut in the apertured teethto inhibit blocking of the axial refrigerant passages formed through thealigned teeth.

Communication between reservoir 44 and the stator teeth is provided byfour circular apertures 50 disposed at 90 intervals along thecircumference of the annular manifold. To as sure a substantially equalvolume of fluid refrigerant passes through each aperture, the diametersof the apertures are dimensioned inversely proportional to the height ofthe liquid reservoir above the aperture. Thus, aperture 50A situated atthe top of the manifold is substantially larger than aperture 508situated at the bottom of the manifold while apertures 50C and 50Dlocated at an intermediate refrigerant elevation have diametersapproximately equal to the median between the diameters of apertures 50Aand 508.

In operation, a liquid refrigerant, for example, REFRIGERANT 11 ispassed from condensor 52 and enters motor through valved conduit 54 at apressure to maintain annular reservoir 44 at a refrigerant elevation inexcess of the elevation of topmost aperture 50A in manifold 42. Therefrigerant then flows through the apertures within the manifold, asindicated by the flow arrows in FIG. 1, into radial zone 56 extendingcompletely through the stator whereupon the refrigerant is diverted inaxially opposite directions through both the aligned triangularly shapedapertures within the stator teeth and motor air gap 40 to be exhaustedthrough orifices 58 situated at opposite ends of the motor. Within themotor, the refrigerant distributes itself according to the pressuredifierential and available area of the diverse axial flow channels (withapproximately percent of the refrigerant desirably passing through thestator teeth) and condenses as droplets optimumly covering the entiresidewalls of the flow channels with a liquid film. As the heat generatedby the stator windings is absorbed by the liquid refrigerant, therefrigerant is converted to a gaseous state and replaced by a succeedingdroplet of refrigerant. Because the refrigerant flows axially througheach tooth of the stator, the refrigerant passes between each end turnof the stator assuring optimum cooling of the end turns. Additionalcooling of the stator end turns also is effected by that portion ofrefrigerant passed through the air gap as the refrigerant flowsdownwardly across the end turns to be exhausted through orifices 58.Typically, the concentration of liquid within the refrigerant issubstantially reduced, e.g. from an 80/20 liquid/gas weight ratio to anapproximately 50/50 liquid/gas weight ratio, by thermal absorption bothwithin the teeth and the air gap prior to arriving at the motor endturns. Moreover, because the centrally admitted refrigerant gentlyscrubs the end turns as the refrigerant passes therebetween (rather thanbeing impelled thereon at a relatively increased velocity as occurs whenthe refrigerant is entered directly into the end turn cavity), therefrigerant has minimum adverse effect on the end turn insulation.

While the optimum refrigerant flow conditions will vary dependent uponsuch factors as the maximum permissible temperature rise within themotor and the axial length of the stator, a typical REFRIGERANT l1compression cycle is illustrated by the temperature-enthalpy curve ofFIG. 4. The refrigerant normally enters the motor cavity or housingcontaining approximately 80 percent liquid refrigerant and a portion ofthe refrigerant evaporates, i.e. along constant temperature line A ofFIG. 4 before being exhausted through orifice 58 with a liquid to gasweight ratio in excess of one. The refrigerant then passes to evaporator60 in a conventional manner, i.e. entering the evaporator below theliquid eliminator (not illustrated), and the remainder of the liquidrefrigerant is converted to a gaseous state before being fed tocompressor 62. In the illustrated case, the REFRIGERANT l1 typically ischaracterized by a pressure of 7.0 psia, a temperature of 40 F. and anenthalpy of 28.3 BTUs/lb. as the refrigerant enters the motor whilerefrigerant exhausted from the motor has an increased enthalpy and anunchanged temperature and pressure. After complete evaporation of therefrigerant in evaporator 60 to raise the enthalpy to approximately 97BTUs/lb. the volume of refrigerant is reduced in compressor 62, i.e.along line B of FIG. 4 to raise the enthalpy of the REFRIGERANT 11 to106 BTUs/lb. at a pressure of 23.6 psia and a temperature of 110 F. Therefrigerant then passes to condensor 52 wherein the enthalpy is reduced,i.e. along line C to 28 BTUs/lb. at a pressure of 23 psia and atemperature of F. whereupon the refrigerant is valved into motor 10.During the valving, the refrigerant is transformed along line D to atemperature of 40 F., a pressure of 7.0 psia and an enthalpy of 28.3BTUs/lb. and the previously described thermal cycle is repeated. Becauseonly a portion of the refrigerant normally need pass through the motor,a bypass line 64 is provided to permit continuous circulation ofrefrigerant not required to cool the motor with suitable valving, e.g.,valves 66 and 68, permitting regulation of the quantity of refrigerantpassing through the motor. Of course, regulation of the pressuredifierential across the motor also can be accomplished without valves bysizing tubing to and from the motor. In one specific operation,efficient cooling of a 720 horsepower motor has been obtained by passingREFRIGERANT ll4 at 15 F. through the motor at a rate of 4.4 gals/min.utilizing the refrigerant flow technique illustrated in FIG. 1. Therefrigerant temperature at the exhaust orifice measured approximately l7F. and a maximum temperature of 81 C. was observed in the motor at theend turns.

When the refrigerant flow rate was increased to 5.2 gals/min. at aninput temperature of 13 F., the friction and windage losses wereobserved to increase and the refrigerant exited the motor at atemperature substantially identical to the temperature of refrigerantentering the motor. The latter flow conditions produced a maximumtemperature of 58 C. along the core of the motor.

An alternate method of providing refrigerant flow through the motor isillustrated in FIG. 5 wherein the refrigerant is admitted at one end ofmotor A and exhausted through an aperture situated at the opposite endof the motor. Desirably, rotor 12A of the motor is provided with anaxial passage 67 extending the length of the rotor and the refrigerantis admitted into the motor through dual orifices 68 disposed in asubstantially confronting attitude with axial passages 67 to direct therefrigerant through the axial passages. A portion of the refrigerantadmitted through orifices 68 also impinges fan blades A of the rotor tobe thrown upon end turns 22A and passed axially along both thetriangularly shaped apertures within the stator teeth and the motor airgap to cool stator 14A. If desired, an auxiliary refrigerant inlet 70can be provided at the end of tubing 72 extending radially inward of thehousing sidewall to permit addition of refrigerant to the motor interiorupon a sensing of an excessive temperature increase by thermostat 76situated within the motor end turns. When the end turn temperatureexceeds the pre-determined limit of the thermostat, a signal is fed backto valve 78 to admit additional refrigerant to the motor end remote fromthe main refrigerant inlet orifices. Similarly, the flow of refrigerantinto the motor can be continuously regulated by automaticallycontrolling the operation of valve 68 of FIG. 1 in response totemperature variations along the length of the motor or the inlet andoutlet pipes may be sized for the maximum operating conditions. Becausethe additional refrigerant enters motor 10A adjacent the rotor fanblades, rapid agitation and vaporization of the refrigerant is assured.Although a thermostat is illustrated in FIG. 5 for controlling the flowof auxiliary refrigerant to the motor, other conditions indicative ofmotor cooling, e.g. the refrigerant pressure at selected locations inthe motor, also can be employed to control the operation of the valve78.

When the stator core is particularly elongated, a refrigerant flow,illustrated in FIG. 6, is utilized wherein the refrigerant enters themotor through orifices 68B situated at opposite ends of the motor insubstantially confronting attitudes with axial passage 67B of rotor 12Band the refrigerant is exhausted through orifice 80 at the center of themotor. A portion of the refrigerant entering the motor through orifices688 also is splashed over the stator end turns adjacent to each inputorifice and passes axially through both the triangular apertures in thestator teeth and the motor air gap prior to exhaust by way of radialpassageway 82 extending through both the stator and rotor. Suitablypassageway 82 can be formed by any conventional method, e.g. positioningspacer blocks between laminations at the center of each structure or bydrilling radial apertures through the rotor and stator, to permitcommunication in a radial direction from the axial passages within themotor to exhaust orifice 80.

In motors having a short stack length and elongated end turns whereinenchanced cooling of the end turns is desired, the cooling systemillustrated in FIG. 7 may be preferred. In this system, the refrigerantis admitted at both ends of the motor through orifices 68C disposed in aconfronting attitude with axial passages 67C and a relatively largeportion of the refrigerant is drawn radially outward over the end turnsto be exhausted through orifices 80C situated below the end turns atboth ends of the motor. A portion of the refrigerant also passes axiallythrough rotor passage 67C to the center of the rotor whereat radialpassageway 84 formed by suitable spacers between the rotor laminationscommunicates the refrigerant with rotor air gap 40C and triangularlyshaped apertures within the stator teeth for passage through the motorin a direction axially opposite the refrigerant flow through rotorpassage 67C. The refrigerant exiting through the stator teeth alsoaugments the end turn cooling produced by the relatively enhanced flowof refrigerant directly across the motor end turns. Desirably, exhaustorifices C are situated axially outboard of input orifices 68C toincrease the percentage of refrigerant passing axially through themotor. In general, a 720 hp motor receiving 3 gals/min. of REFRIGERANT114 at 14 F. at each end of the motor along the flow path illustrated inFIG. 7 was found to exhibit a maximum temperature of only 45 C. alongthe length of the stator. By increasing the refrigerant input flow ateach end of the motor to 5.3 gals/min. at a temperature of 17 F., themotor output could be raised to 900 hp with a maximum temperature of 72C. along the stator.

Because of the tendency for the refrigerant to become less effective asa heat sink with increased passage through the stator, generally overallsuperior motor cooling was obtained when the liquid refrigerant wasintroduced both at one end and the center of the motor and exhaustedthrough orifices situated at both ends of the motor as illustrated inFIG. 8. Desirably, exhaust orifice A situated at the inlet end of themotor is smaller than exhaust orifice 858 at the opposite inlet end ofthe motor to produce a refrigerant flow direction toward the oppositeinlet end (as illustrated by the arrows in FIG. 8). Thus, a portion ofthe refrigerant enters the motor through orifices 68D positioned in aconfronting attitude with axial passage 67D through rotor 12D and therefrigerant distributes itself between air gap 40D and the axial flowchannels in the stator teeth and the rotor with some refrigerant passingover the end turns to be exhausted through orifice 85A. As the portionsof the refrigerant passing axially through motor 10D deposit as dropletsupon the walls of both the stator and the rotor to be converted to agaseous state, the quantity of liquid within the flowing refrigerantvapor is reduced tending to diminish the cooling capacity of therefrigerant. However, by the addition of refrigerant to the motorthrough centrally disposed orifice 86, augmented cooling of the motor iseffected along the half of the stator situated remote from inputorifices 68D. Because one refrigerant inlet, i.e. input orifices 68D, issituated directly adjacent to the end turn cavity while the secondrefrigerant inlet, i.e. orifice 86, is situated at the center of themotor remote from the end turns, uniform cooling of the motor isobtained. In one specific instance, a 720 hp motor having a refrigerantflow as illustrated in FIG. 8 and utilizing refrigerant 114 inputs of3.5 gals/min. at 16 F. through central orifice 86 and 1.5 gals/min. at16 F. through input orifices 68D was found to have a maximum temperatureof 68 C. located in the stator end turns. When the flow rate was changedto 5.0 gals/min. at the input end of the motor and 3.0 gals./min. at thecenter of the motor, the motor was operated at an increased horsepowerof 996 with a maximum temperature of 77 C. being produced in the statorend turns.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a dynamoelectric machine, the combination comprising a statorformed of a plurality of axially aligned magnetic larninations stackedto form a cylindrical bore for reception of a rotor therein, saidlaminations having a circular yoke and a plurality of teeth extendingradially inward from said yoke to provide slots along the length of saidstator for insertion of machine windings therein, each of said teethexhibiting a gradually decreasing width with increased span from thestator yoke, and a triangularly shaped aperture situated entirely withineach of said teeth at an attitude to provide a constant flux carryingarea over the length of each of said teeth, the sides of saidtriangularly shaped apertures adjacent said slots being disposedparallel to the adjacent tapered sides of said tooth at an attitude toconverge at the tooth face confronting said bore to produce a total fluxcarrying area within said tooth at any radial location along the strutsformed between the aperture and said slots substantially equal to theflux carrying area of the tooth face confronting said cylindrical bore,and means for passing a fluid refrigerant through the triangularlyshaped apertures in an axial direction.

2. A dynamoelectric machine according to claim 1 wherein said means forpassing fluid refrigerant through said triangularly shaped aperturescomprises an annular manifold centrally disposed along the length ofsaid stator and a plurality of orifices of diverse cross-sectional areaswithin said manifold to communicate said fluid refrigerant with theapertured stator teeth.

3. A dynamoelectric machine comprising a stator formed of a plurality ofmagnetic laminations stacked to form a cylindrical bore, each of saidlaminations having a completely homogeneous circular yoke and aplurality of teeth extending radially inward from said yoke to providearcuately displaced slots extending the axial length of said stator,each of said teeth having tapered sides to produce parallel faces onadjacent teeth, machine windings disposed within said slots with the endturns of said windings protruding outwardly from the ends of the stackedlaminations, an aperture situated entirely within each of said teeth,the sides of said aperture being parallel to the adjacent sides of saidassociated tooth at an attitude to converge at the center of the toothface confronting said bore to provide a total flux carrying area at anyradial location along the struts formed between said aperture and saidslots substantially equal to the flux carrying area of the tooth faceconfronting said bore, means for passing a fluid refrigerant throughsaid apertures in an axial direction, and a rotor disposed within saidstator bore for electromagnetic interaction therewith.

4. A dynamoelectric machine according to claim 3 further including anaxial channel within said rotor for the passage of fluid refrigeranttherethrough, a first nozzle disposed in a substantially confrontingattitude relative to said axial channel for propelling said fluidrefrigerant toward said channel, a second nozzle situated at the end ofsaid machine remote from said first nozzle, said second nozzle beingdisposed in a confronting attitude relative to said axial channel withinsaid rotor and further including aligned radial passages extendingthrough said stator and said rotor at the axial center of said machinefor removal of fluid refrigerant from said machine.

5. A dynamoelectric machine according to claim 3 further including anaxial channel within said rotor for the passage of fluid refrigeranttherethrough, a first nozzle disposed in a substantially confrontingattitude relative to said axial channel for propelling said fluidrefrigerant toward said channel, a second fluid refrigerant inletorifice situated along the length of said stator in communication with aradial zone extending through said stator laminations and a fluidrefrigerant exhaust orifice situated at the end of said machine remotefrom said noale.

6. A dynamoelectric machine according to claim 5 wherein said radialzone extending through said stator laminations is in axial registrationwith a radial zone extending into said rotor and further including anaxial passage extending the length of said stator.

7. In a dynamoelectric machine, the combination comprising a statorformed of a plurality of magnetic laminations stacked to form acylindrical bore, said laminations having a circular yoke and aplurality of teeth extending radially inward from said yoke to provideaxially extending slots along the length of said stator, a plurality ofapertures situated within said magnetic laminations and extending atleast partially within said teeth, a machine housing circumferentiallyenclosing said laminations, and an annular manifold disposed along theaxial length of said stator to provide a liquid refrigerant reservoirbetween said manifold and housing extending to at least the center ofsaid stator, said manifold having a plurality of orifices communicatingsaid reservoir with said apertures in said stator teeth, thecross-sectional area of said orifices varying inversely with the heightof said reservoir above each orifice.

8. A dynamoelectric machine according to claim 7 wherein said apertureswithin said teeth are triangularly shaped and said manifold is furthercharacterized by a plurality of radially inwardly extending platesspaced at arcuately displaced locations along said manifold.

9. A dynamoelectric machine according to claim 8 wherein said manifoldhas a diameter less than the diameter of said magnetic laminations, saidplates are equal in number and arcuate displacement to said stator teethand further including means within said plates for communicating areasdisposed on opposite sides of said plates.

1. In a dynamoelectric machine, the combination comprising a statorformed of a plurality of axially aligned magnetic laminations stacked toform a cylindrical bore for reception of a rotor therein, saidlaminations having a circular yoke and a plurality of teeth extendingradially inward from said yoke to provide slots along the length of saidstator for insertion of machine windings therein, each of said teethexhibiting a gradually decreasing width with increased span from thestator yoke, and a triangularly shaped aperture situated entirely withineach of said teeth at an attitude to provide a constant flux carryingarea over the length of each of said teeth, the sides of saidtriangularly shaped apertures adjacent said slots being disposedparallel to the adjacent tapered sides of said tooth at an attitude toconverge at the tooth face confronting said bore to produce a total fluxcarrying area within said tooth at any radial location along the strutsformed between the aperture and said slots substantially equal to theflux carrying area of the tooth face confronting said cylindrical bore,and means for passing a fluid refrigerant through the triangularlyshaped apertures in an axial direction.
 2. A dynamoelectric machineaccording to claim 1 wherEin said means for passing fluid refrigerantthrough said triangularly shaped apertures comprises an annular manifoldcentrally disposed along the length of said stator and a plurality oforifices of diverse cross-sectional areas within said manifold tocommunicate said fluid refrigerant with the apertured stator teeth.
 3. Adynamoelectric machine comprising a stator formed of a plurality ofmagnetic laminations stacked to form a cylindrical bore, each of saidlaminations having a completely homogeneous circular yoke and aplurality of teeth extending radially inward from said yoke to providearcuately displaced slots extending the axial length of said stator,each of said teeth having tapered sides to produce parallel faces onadjacent teeth, machine windings disposed within said slots with the endturns of said windings protruding outwardly from the ends of the stackedlaminations, an aperture situated entirely within each of said teeth,the sides of said aperture being parallel to the adjacent sides of saidassociated tooth at an attitude to converge at the center of the toothface confronting said bore to provide a total flux carrying area at anyradial location along the struts formed between said aperture and saidslots substantially equal to the flux carrying area of the tooth faceconfronting said bore, means for passing a fluid refrigerant throughsaid apertures in an axial direction, and a rotor disposed within saidstator bore for electromagnetic interaction therewith.
 4. Adynamoelectric machine according to claim 3 further including an axialchannel within said rotor for the passage of fluid refrigeranttherethrough, a first nozzle disposed in a substantially confrontingattitude relative to said axial channel for propelling said fluidrefrigerant toward said channel, a second nozzle situated at the end ofsaid machine remote from said first nozzle, said second nozzle beingdisposed in a confronting attitude relative to said axial channel withinsaid rotor and further including aligned radial passages extendingthrough said stator and said rotor at the axial center of said machinefor removal of fluid refrigerant from said machine.
 5. A dynamoelectricmachine according to claim 3 further including an axial channel withinsaid rotor for the passage of fluid refrigerant therethrough, a firstnozzle disposed in a substantially confronting attitude relative to saidaxial channel for propelling said fluid refrigerant toward said channel,a second fluid refrigerant inlet orifice situated along the length ofsaid stator in communication with a radial zone extending through saidstator laminations and a fluid refrigerant exhaust orifice situated atthe end of said machine remote from said nozzle.
 6. A dynamoelectricmachine according to claim 5 wherein said radial zone extending throughsaid stator laminations is in axial registration with a radial zoneextending into said rotor and further including an axial passageextending the length of said stator.
 7. In a dynamoelectric machine, thecombination comprising a stator formed of a plurality of magneticlaminations stacked to form a cylindrical bore, said laminations havinga circular yoke and a plurality of teeth extending radially inward fromsaid yoke to provide axially extending slots along the length of saidstator, a plurality of apertures situated within said magneticlaminations and extending at least partially within said teeth, amachine housing circumferentially enclosing said laminations, and anannular manifold disposed along the axial length of said stator toprovide a liquid refrigerant reservoir between said manifold and housingextending to at least the center of said stator, said manifold having aplurality of orifices communicating said reservoir with said aperturesin said stator teeth, the cross-sectional area of said orifices varyinginversely with the height of said reservoir above each orifice.
 8. Adynamoelectric machine according to claim 7 wherein said apertureswithin said tEeth are triangularly shaped and said manifold is furthercharacterized by a plurality of radially inwardly extending platesspaced at arcuately displaced locations along said manifold.
 9. Adynamoelectric machine according to claim 8 wherein said manifold has adiameter less than the diameter of said magnetic laminations, saidplates are equal in number and arcuate displacement to said stator teethand further including means within said plates for communicating areasdisposed on opposite sides of said plates.